1. Field of the Invention
The invention relates to a vehicle gateway device to be installed in an automotive vehicle, to a communication data control method and to a computer program product therefor.
2. Description of the Related Art
A vehicle gateway device for an automotive vehicle includes a relay function unit and a network management function unit. The relay function unit judges whether communication data flowing on a bus line connected with the vehicle gateway device is relay data and governs a relay function of transmitting this relay data on the bus line after amplification or the like. Since the relay data is frequently sent out from a node of the bus line, a high speed process is required. The network management function unit performs a network management process in accordance with communication data flowing on the bus line if this communication data is network management data. However, network management data are received far less frequently than the relay data. Thus, processes of the network management function unit are not as fast as those of the relay function unit.
In the conventional vehicle gateway device, the relay function unit and the network management function unit are constructed by a microcomputer or an ASIC (Application Specific Integrated Circuit).
U.S Patent Application Publication No. 2003/0117298 discloses a vehicle gateway device capable of confirming the content of a data packet transmitted to an OEM bus 103 and an ITS data bus 105, determining whether this data packet is to be transferred to another bus according to the content thereof and ensuring traffic by eliminating the flow of unnecessary data.
U.S. Patent Application Publication No. 2003/0223436 discloses a network management system, in which a network manager switches a network segment off to switch subscriber units off if the subscriber units are not needed by another network segment.
However, if the relay function unit and the network management function unit are constructed by a microcomputer, a high-performance microcomputer needs to be employed to realize the relay function unit required to perform a high speed process. Such a high-performance microcomputer causes an overengineering problem for the network management function unit. On the other hand, if the relay function unit and the network management function unit are constructed only by an ASIC, there is a problem of being difficult to add a new function to the network management function unit. These problems are not solved easily because the network management function unit and the relay function unit are not constructed by different devices.
An object of the invention is to provide a vehicle gateway device and a control method to performing processes of a relay function unit and easily adding a new function to a network management function unit without employing a high-performance microcomputer.